In the early eighteenth century, Edinburghwas a filthy backwater synonymous with poverty and disease, and recently famous for religious persecution. When this small walled-off city surrendered to a handful of Highlanders in 1745, things had never looked bleaker. Yet by century's end, the ancient Scottish capital had become the marvel of modern Europe, thanks to a group of friends whose trailblazing ingenuity and passion for ideas changed the way all of us look at the world.

It was in Edinburgh that a unique gathering of the finest minds of the day came together and made breathtaking innovations in architecture, politics, science, the arts and economics, all of which continue to echo loudly today. This was a time of radical upheaval and advancement, and a place of such cerebral stature as to rival the Athens of Socrates. Adam Smith penned The Wealth of Nations. James Boswell produced The Life of Samuel Johnson. Alongside them, pioneers -- such as the philosophers David Hume and Adam Ferguson, the poet Robert Burns, the chemist James Black, the geologist James Hutton, and the novelist Sir Walter Scott -- transformed the way we understand our perceptions and feelings, sickness and health, relations between the sexes, the natural world, and the purpose of existence.

In Crowded with Genius, James Buchan, himself a Scot with a strong attachment to this history, beautifully reconstructs the intimate geographic scale and boundless intellectual milieu of Enlightenment Edinburgh. With the scholarship of a historian and the elegance of a novelist, he tells the story of the triumph of this unlikely town and the men whose vision brought it into being. Buchan has written an extraordinary account of the movement that turned Edinburgh from a city under siege into a hotbed of brilliant achievements that changed the course of history and gave birth to the modern mind.

Analysing the Scottish Enlightenment is a monumental task. Controversies and inconsistencies abound. This Calvinist society rose to support a Roman Catholic pretender to the British throne. While condemning the Papacy as intruding on the lives of the faithful, the Scottish Kirk was thoroughly integrated into the education, politics and legal system of Edinburgh. Buchan neatly ties all these conflicting forces into a readable, highly detailed package. He is able to expose all these facets with minimal confusion as he introduces us to the major figures that would make the city a northern Athens. His focus is on personalities, with leading figures ambling, cavorting or dashing across the pages according to their style.

His first noteworthy figure is, of course, David Hume. Perhaps no individual set the tone for the Scottish Enlightenment as did Hume. Controversial and inconsistent in his own way, he struggled to shed the impediments of traditional dogmas while avoiding accusations of rebellion or heresy. He set the tone Edinburgh lights would follow - travelling the Continent, examining the human condition, and writing in "Southern English", as Buchan calls it. The language of London was a key element in what was to follow. English, instead of "Scottish English" would be the export licence conveying ideas up and down the British island, thence abroad.

Hume is followed by such notables as Adam Smith, John Home, the strange saga of James MacPherson's attempt to resurrect Scots' traditions by fabricating them, and the founder of geology, James Hutton. Other, lesser known lights, but surely contributors to this Northern Renaissance are dramatist Alexander Wedderburn, publisher Robert Chambers and the more practical contributions of George Drummond. There is more to Edinburgh's rise to prominence than the expressions of thoughtful men. In this period, the city descended from an enclave surrounding its "castle in the air" to build up the surroundings with residences, schools and market centres. The "salacious" hobbies of dance and the theatre intruded on the Kirk's disdain and overcame it. Promenading, weather permitting, was no longer hazardous. Although whisky replaced ale as the most consumed drink, imbibing moved from ale house to town house. This practice helped enable the role women to improve and conversations expanded to include both sexes.